1. Field of the Invention
The present invention relates to drilling apparatus. More particularly, the present invention pertains to mobile drilling apparatus for operation on unfavorable terrain and for drilling at various angles with respect to the surface.
2. Description of Prior Art
Current practices in drilling holes in the ground employ a variety of apparatus. In particular, relatively shallow holes for such purposes as setting pilings or placing charges for seismic exploration may be drilled by a pile driver or by conventional well-drilling equipment. Where many such holes must be drilled, such as the case where pilings to support a pipeline are to be positioned, the drilling equipment must be frequently moved to new drilling sites. The usual method of moving a drilling rig is by "skidding," or by utilizing a rig mounted on a truck. Such a drilling operation requiring extensive movement of the equipment between multiple drilling sites can be impractical, however, or even virtually impossible, with such conventional drilling rigs where the terrain is rough, marshy or icy. In cases where the climate is extreme, as much of the total operation as possible must be capable of being performed in a sheltered environment. Furthermore, the drilling apparatus must be capable of drilling holes at various angles with respect to the surface, as needs dictate.